Superheating system



Nb. 753,433. I PATENTED MAR. 1, 1904. S. A. REEVE.

SUPERHEATING SYSTEM.

APPLICATION FILED APR. 27. 1903.

N0 MODEL.

CC. C I 739M149 UNITED STATES Patented March 1, 1,904.

PATENT OFFICE.

SIDNEY A. REEVE, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CHARLES F.BROWN, TBUSTEILOF READING, MASSACHUSETTS.

SUPERHEATING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 753,433, dated'March 1,1904.

Applicationfile d April 27, 1903. Serial No. 154,405. (No model.)

To all whom it may concern:

Be it known that I, SIDNEY A. Rnnvn, of Worcester, in the county ofWorcester and State of Massachusetts, have invented certain new anduseful Improvements in Superheating Systems, of which the following is aspecification.

This invention has for its object to furnish to steam-engines or otherdevices a steamsupply having a moderate and constant degree ofsuperheat.

In the superheaters which are familiar to the public the steam issupplied to the superheater in a saturated condition and is superheatedby contact with metallic surfaces which are heated from the other sideby hot gases coming more or less directly from the furnace-fire. Amongthe faults of this plan may be mentioned the following: first, rapiddeterioration of the metallic surfaces, owing to their being exposed onone side to a hot drycumulation of soot and ashes on the fire side ofthe surfaces; fourth, destructive eifect on engine or super-heater, orboth, due to the wide variation in degree of superheat which takes placewhen a variation in the demand for steam or a variation in the supply offur nace-gases occurs.

The present invention consists in a superheating system or apparatuswhich obviates these faults and provides instead a stable supply ofsteam for the engine at a constant degree of superheat from apparatus ofa'durable nature independently of the variable conditions occurring inpractice.

Of the accompanying drawings, Figure 1 represents a perspective view ofa superheating system embodying my invention. Fig. 2 represents asectional view of the release-valve controlling communication betweenthe highpressure and the low-pressure boiler.

The same reference characters indicate th same parts in both figures.

I ard type provided with suitable furnaces and in practice having theusual accessories, many of which I have omitted to show in the drawings,and 11 11 are branch steam-pipes connected to a steam conduit or supplypipe 12, which leads to a translating device, such as the engine 13.

14 is a boiler or steam-generator of a suitable type built to withstandpressures considerably higher than those employed in the boilers '10 andhaving a furnace and the usual accessories. A pipe 15 leads from thesteam space of the boiler 14 to a coil 16, contained in a drum orenlargement 17 in the steam-conduit 12, and from said coil a pipe 18returns to the water-space of the boiler 14. Between the drum 17 and theengine 13 is a throttlevalve 19 in the steam-conduit 12.

20 20 are thesafety-valves of the boilers 10, and 21 is the regularsafety-valve of the boiler 14, set to release at a higher pressure thanthe valves 20. I p

22 is a release-conduit connecting the steamspace of the boiler 14 withthe interior of one of the boilers 10 and containing a safety-valvemechanism 23, the valve 24 of which is loaded by a spring 25, so thatwhen the difference in pressures between the boiler 14 and the boilers1O exceeds the pressure of the spring communication will be establishedbetween said boilers 14 and 10. The stem of valve 25 has a nut 26,whereby the valve may on occa sion be held permanently open. It is notessential that the release-conduit 22 shall connect directly with theshell of boiler 10, and

in referring to this connection in the claims it will be understood thatthe term steamgenerator or similar term includes also the piping andother connections of the boilerproper. The valve 21 is set to release ata higher pressure than the valve 23 and is not strictly a necessaryelement during the normal operation of the system.

In operation the boilers 1O 10 supply steam in the regular way throughthe conduit 12 to the engine 13, the said steam passing through theinterior of drum 17 in contact with the coil 16. The steam supplied bythe boiler 14 to the coil 16 through pipe 15 being of much higherpressure than the engine-supply, and hence of a higher temperature, willsuperheat the steam in drum 17 by conduction of heat through the wallsof the coil 16, and'this superheating steam in the coil will be more orhowever, either because the boiler 14 is firedtoo strongly or becausethe draft through the drum 17 is too small, the surplus steam formed inboiler 14 passes through the valve mechanism 23 and conduit 22 into theboilers 1O 10. The capacity of the latter being preferably much largerthan that of boiler 14, they will under most circumstances be sufficientto store this steam coming from 14 for future use. If not, it escapesthrough the safety-valves 2O 20 and gives warning of too hot fires. Theonly detrimental result would be a slight loss of efliciency. Inpractice the heat of the fires under the several boilers can beregulated approximately, according to the demand ,for steam, by theusual automatic appliances, such as damper-regulators, 620.

Several advantages of the invention will be evident, and among them maybe named the following:

First. The surfaces taking the high-temperature heat from the fire(those of the boiler 14) are coated on their steam side by either wateror wet saturated steam instead of by dry superheated gaseous steam, asin the ordinary superheater. They will therefore have the durability ofan ordinary boiler.

Second. The surfaces imparting the superheat to the working steam (thoseof the coil 16) are coated at their upper end with wet saturatedhigh-pressure steam on one side and with wet saturated low-pressuresteam on the other side and at their lower end with very wet high-pressure steam or water of condensation on one side and withsuperheated steam on the other. The heat transmission per unit ofsurface will therefore be rapid.

Third. For the same reason these surfaces will be durable.

Fourth. As the temperatures are controlled by the pressure in the boiler14, they are entirely independent of either the rate of firing or therate of steam consumption in connection with the boilers furnishing thesteamsupply to the engine.

'Fifth. There is no danger to the engine from excessive superheat.

Sixth. No special knowledge or skill in attendance is necessary.

Seventh. The special construction and extra cost involved are only thecost of simple superheating devices, such as the coil 16 and drum 17 andthe cost of extra strength in the boiler 14.

Eighth. At any time that operation under superheat becomes undesirable,either temporarily or permanently, the safety-valve 24 may be held openand the boiler 14 operated at low pressure, as one with the battery 1010.

Ninth. The question of distance of location of the engine from theboiler-room as affecting the degree of superheat disappears. Howevermuch condensation may occur in either of the pipe-lines 12 or 15 18, dueto distance, so long as the capacity of the boiler 14 is such that saidboiler is able to maintain normal high pressure in the coil the degreeand constancy of superheat will not be affected. In other words, thedegree of superheat is determined solely by the pressure in boiler 14.This is easily kept constant under ordinary working conditions and willvary only when the engine is so overloaded that the capacity of eitherthe boiler 14 or the coil 16 is exceeded. In such a case a portion ofthe normal superheat is lost; but the efficiency is not appreciablyaffected from this cause, because at overload superheat is of littleeffect in maintaining efficiency. This temporary loss of superheat doesnot affect the durability of the engine, as is the case with theordinary superheater.

It will be understood that the details in the manner of practicing thisinvention may be considerably modified without departing from theprincipleinvolved. It will be further understood that therelease-conduit 22 and safety-valve 23 are "adopted principally as ameasure of economy, so that should the boiler 14 be overfired steam willnot be lost. In practice the proper pressures are intended to bemaintained by proper firing and that of the boiler 14 would be keptbelow the pressure at which release occurs. There are also equivalentdevices which might be made to subserve substantially the same functionas the elements 22 23. Hence, although these elements or theirequivalents would preferably be employed in aworking apparatus, theprocess is normally carried on without calling their functions intoaction, and for this reason they are not absolutely essential to theinvention in its simplest form.

The method herein described is made the subject of a separateapplication filed concurrently herewith, Serial No. 154,406.

Different equivalents may be employed for the form of superheater 16 17herein shown; but for the best results with economy of space thereshould be, as in the device illustrated, two steam-chambers with areplicate divisionthat is, a wall or separating structure whoseconvolutions, sections,units, folds, divisions, legs, tubes, or the likeare repeated sufliciently to give the required heat-transferringsurface.

I claim 1. In a superheating system, a lower-pressure steam-generatorfor supplying working steam, a higher-pressure steam-generator forsupplying steam to superheat the working steam, a superheaterconstructed with two chambers having a replicate division, and conduitconnections between said chambers and the steam-spaces of the respectivesteam-generators.

2. In a superheating system, two steam-generators arranged for differentsteam pressures, a translating apparatus having a conduit connectionwith the lower-pressure generator, and a superheater having chambers inheat-transferring relation, one of which is interposed in the connectionbetween lowerpressure generator and translating apparatus, the otherhaving a conduit connection with the higher-pressure generator.

3. In a superheating system, a generator for supplying Working steam, asecond generator for supplying superheating steam, conduit connectionsforming a loop emanating from the steam-space of thesuperheating-generator and returning to said generator, and asuperheater having chambers in heat-transferring relation, one of whichis included in said loop, the other having a conduit connection with theworking steam-generator and an outlet for connection with a translatingapparatus.

4. In a superheating system, generators for supplying working andsuperheating steam respectively, a conduit connection between the SIDNEYA. REEVE' Witnesses:

R. M. PIERSON, A. C. RATIGAN.

